Question

An engineer has designed a valve that will regulate water pressure on an automobile engine. The valve was tested on 190 engines and the mean pressure was 6.0 pounds/square inch (psi). Assume the population standard deviation is 0.8 . If the valve was designed to produce a mean pressure of 6.1 psi, is there sufficient evidence at the 0.02 level that the valve does not perform to the specifications? Step 1 of 6 : State the null and alternative hypotheses.

Answer 1

Explanation:

Step 1 of 6: State the null and alternative hypotheses.

The null hypothesis (H0) is that the valve performs to the specifications, meaning that the true mean pressure of the population is equal to 6.1 psi.

H0: μ = 6.1

The alternative hypothesis (Ha) is that the valve does not perform to the specifications, meaning that the true mean pressure of the population is less than 6.1 psi.

Ha: μ < 6.1

To clarify, this is a one-tailed test to the left, as we are only interested in knowing if the mean pressure is significantly less than 6.1 psi.